Chargers safety Kevin Ellison simply didn’t want to run out of pain pills and did not know the Vicodin in his possession was a controlled substance, according to his agent.

“He thought it was a good idea to get enough pain killers to last the season,” Jerome Stanley said Tuesday, the day after Ellison was arrested in possession of 100 pills of Vicodin. “They were for him to use because of his knee surgery.”

Ellison was charged with one count of possession of a controlled substance after being stopped for speeding in Redondo Beach. Redondo Beach police say he was going 40 mph in a 25-mph zone, prompting police to pull over Ellison’s 2009 Audi. Ellison was alone in the car.

“There was something in the (arresting) officer’s mind that arose suspicion,” Redondo Beach Sgt. Phil Keenan said. “I don’t know if it was the way Kevin was acting. I don’t know what it was. I have not talked to the officers. But Kevin gave the officers consent to search the car. They asked if there was anything illegal in the car and he said no. They asked if it was OK to search, and he allowed them to search. That’s when they found, in the center console, the 100 Vicodin.”

He was released on $10,000 bail.

Ellison, who played at Redondo Union High School and USC, did not immediately return a message Tuesday. His family declined to comment.

“He’s a little embarrassed,” Stanley said.

Stanley said he did not know where Ellison got that quantity of pills but said Ellison did not want to have to “go back and forth” and “have to bother anyone” for the pills.

Ellison had three knee surgeries in college, including one that ended his senior season at USC. He said in an interview last week, “My knees feel great. They really do.”

Ellison, 23, was a sixth-round draft pick last year and started nine games at strong safety.

He is in a battle for playing time going into the 2010 season after the Chargers drafted Darrell Stuckey in the fourth round.

Many who have used Vicodin have become addicted to it. Former Chargers quarterback Ryan Leaf was sentenced to 10 years of probation last month after pleading guilty to eight felony drug charges related to his admitted addiction to Vicodin. Leaf said his addiction started after surgeries to his shoulders, knees and wrist from his career in the NFL.

“Vicodin is a horribly abused drug,” Keenan said. “It’s not uncommon to arrest people for possession of Vicodin.”

The case will be referred to the Los Angeles District Attorney for review. Ellison is due to appear in Torrance Superior Court on the charge in July.